1. Field of the Invention
The present invention relates to a storm window construction and more particularly to a storm window construction utilizing flexible clear plastic membranes stretched in parallel spaced relation to the window glass to provide an insulating layer of air between the glass and the membrane and to the means for securing the membrane to a window casing.
2. Description of the Prior Art
The use of a flexible clear plastic membrane attached to a window frame in parallel spaced relation to a pane of window glass to provide an insulating layer of air between the glass and the membrane is well known. Commonly the membrane is secured to the window frame outside of the glass using wooden framing strips nailed to the window frame. However, applying the membrane outside of the glass is often unsatisfactory because it may require climbing a ladder to reach the window, or the weather may be cold, rainy or windy, making installation difficult. Furthermore, wooden framing strips have proved unsatisfactory because they are usually made of poor quality thin wood lath and often splinter or split when nailed in place. Furthermore, such wooden strips are unsightly and detract from the appearance of the building. Also, with the membrane installed outside the window glass, it, too, becomes unsightly if not installed under sufficient tension, and furthermore can stretch or rip when exposed to extreme cold and higher winter winds.
Various types of framing strips and bead strips have been suggested for securing the edges of clear plastic film along opposite sides of a window opening. However, most such framing strips require that the strip be attached to the window frame itself, a molding associated with the frame or at the juncture of the window frame or its molding and the window casing, as exemplified by Keegan et al U.S. Pat. No. 3,371,702. Also in many cases special frames incorporating an integral membrane framing strip are used as exemplified by Saling U.S. Pat. No. 3,187,801.Framing strips that are applied directly to the window frame itself are shown in Commiso U.S. Pat. No. 3,068,939, and British Pat. No. 1,037,236. Attachment of a framing strip directly to the window frame or sash is often difficult, especially if the frame or sash is metal.
Framing strips commonly have a groove for receiving a complementary shaped bead strip for securing an edge portion of the clear plastic membrane within the groove of the framing strip. Such an arrangement is also shown, for example, in the previously mentioned Keegan et al, Saling and British patents. However, a common problem with such bead strips is that they tend to pull out of their grooves when the membrane is placed under tension between the bead and the walls of the groove.
Another common drawback of plastic window membranes is that they prevent the covered window from being opened to admit fresh air when desired.